Construction of a Prediction Model for Three-dimensional(3D)Dose Distribution of Iodine-131 Based on SPECT/CT Radiomics Features

ZHANG Wen-sheng; HUANG Wei-kun; LAN You-xi

Abstract：Objective: To construct a prediction model for three-dimensional (3D) dose distribution of iodine-131 based on SPECT/CT radiomics features. Methods: A multi-scale feature pyramid network (MSFPN) was used to extract heterogeneity features of thyroid tissues before and after iodine-131 treatment. A spatiotemporal modeling framework (MSFPN+CNN+GAT+3D model) integrating convolutional neural network (CNN) and graph attention network (GAT) was established to achieve precise dose distribution prediction. Clinical and imaging data from 320 patients at a tertiary hospital were divided into training, validation, and test sets at a 7∶2∶1 ratio. The models were evaluated for iodine-131 residence time and time-activity curves (TACs) of key target organs. Predictive accuracy was assessed using root mean square error (RMSE), mean absolute error (MAE), and gamma index. Results: The residence time of iodine-131 in the thyroid, bladder, and stomach was longer than that in the bone marrow (P<0.05). Following iodine-131 treatment, the activity curve of bone marrow showed minimal variation over time. The bladder tissue exhibited an initial increase in activity, reaching its peak at 4 h, followed by a gradual decline. Both the thyroid and gastric tissues demonstrated a decreasing trend in activity over time, with the gastric tissue displaying even lower dose levels compared to the thyroid. The RMSE and MAE of the MSFPN+CNN+GAT+3D model for the dose distribution of each target organ were lower than those of the MSFPN, ResNet and 3D CNN models, and the γ index was higher than those of the MSFPN, ResNet and 3D CNN models (P<0.05), and there was no statistical significance when compared with the ensemble model (P>0.05). Conclusion: The MSFPN+CNN+GAT+3D model systematically captures deep radiomics features, effectively facilitating the imaging evaluation of the accurate dose distribution of multiple organs during radioactive iodine-131 treatment.